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Abstract PremiseAs the sister clade to angiosperms, extant gymnosperms are crucial for reconstructing ancestral gene regulatory networks in seed plants. This highlights the need for model systems representing each of their distinct lineages. However, tools to quickly and effectively investigate gene function in gymnosperms are still limited due to the challenges of long life cycles and large genome sizes. Species within the xerophytic genusEphedra(Gnetales) have comparatively smaller genomes and shrubby growth habits with shorter life spans, making them better suited for greenhouse cultivation and laboratory experiments. MethodsWe implement virus‐induced gene silencing (VIGS) to manipulate gene expression inEphedra tweedieanaviaAgrobacterium‐mediated vacuum infiltration of tobacco rattle virus (TRV1 and TRV2) into seedlings. ResultsTreatment resulted in highly efficient gene silencing of theE. tweedieana PHYTOENE DESATURASE(PDS) orthologEtwPDS. The expected photobleaching phenotype was observed as early as two weeks, and lasted at least five months in stems, shoot tips, leaves, axillary meristems, and lateral branches of treated plants. DiscussionWe report on virus‐induced targeted gene silencing ofPDSin a Gnetales representative to further enable functional studies of the genetic mechanisms underpinning adaptations in gymnosperms, an important and underrepresented lineage of seed plants. 

Abstract PremisePteridophytes—vascular land plants that disperse by spores—are a powerful system for studying plant evolution, particularly with respect to the impact of abiotic factors on evolutionary trajectories through deep time. However, our ability to use pteridophytes to investigate such questions—or to capitalize on the ecological and conservation‐related applications of the group—has been impaired by the relative isolation of the neo‐ and paleobotanical research communities and by the absence of large‐scale biodiversity data sources. MethodsHere we present the Pteridophyte Collections Consortium (PCC), an interdisciplinary community uniting neo‐ and paleobotanists, and the associated PteridoPortal, a publicly accessible online portal that serves over three million pteridophyte records, including herbarium specimens, paleontological museum specimens, and iNaturalist observations. We demonstrate the utility of the PteridoPortal through discussion of three example PteridoPortal‐enabled research projects. ResultsThe data within the PteridoPortal are global in scope and are queryable in a flexible manner. The PteridoPortal contains a taxonomic thesaurus (a digital version of a Linnaean classification) that includes both extant and extinct pteridophytes in a common phylogenetic framework. The PteridoPortal allows applications such as greatly accelerated classic floristics, entirely new “next‐generation” floristic approaches, and the study of environmentally mediated evolution of functional morphology across deep time. DiscussionThe PCC and PteridoPortal provide a comprehensive resource enabling novel research into plant evolution, ecology, and conservation across deep time, facilitating rapid floristic analyses and other biodiversity‐related investigations, and providing new opportunities for education and community engagement. 

Abstract Imperfect historical records and complex demographic histories present challenges for reconstructing the history of biological invasions. Here, we combine historical records, extensive worldwide and genome-wide sampling, and demographic analyses to investigate the global invasion of Mimulus guttatus from North America to Europe and the Southwest Pacific. By sampling 521 plants from 158 native and introduced populations genotyped at >44,000 loci, we determined that invasive M. guttatus was first likely introduced to the British Isles from the Aleutian Islands (Alaska), followed by admixture from multiple parts of the native range. We hypothesise that populations in the British Isles then served as a bridgehead for vanguard invasions worldwide. Our results emphasise the highly admixed nature of introduced M. guttatus and demonstrate the potential of introduced populations to serve as sources of secondary admixture, producing novel hybrids. Unravelling the history of biological invasions provides a starting point to understand how invasive populations adapt to novel environments. 

Trans-Beringia taxa often present complex puzzles for taxonomists, a reflection of differing traditions and opinions, taxonomic approaches, and access to material from both sides of the Bering Strait. There is wide biological variation in perceived or circumscribed taxa whose populations are widespread within the regions and yet biogeographically isolated in Asia and/or America. The Claytonia arctica complex is one such example; it illustrates these issues well and has been dealt with by North American and Russian botanists in decidedly different ways. We reviewed specimens and examined the various taxonomic concepts of C. arctica through time and source publications. The relationships (alignments) among taxonomic concepts are presented in a graphical format. We found that much of the confusion related to C. arctica in Beringia stems from overlookingC. scammaniana Hultén sensu Hultén (1939), and placing too much emphasis on the woody caudex and perennation structures, during the creation of two taxonomic concepts: C. arctica Adams sensu Porsild and C. porsildii Jurtzev sensu Yurtsev. The C. arctica complex (in our current sense) is an evolutionary work in progress, resulting in partially differentiated races with much overlapping variability and intergradation of characters (particularly in C. scammaniana according to our current sense) that have not reached the level of stability (i.e., individuals may still intergrade freely) usually associated with the concept of species in other arctic lineages.